Install Tracelet

Mount the tracelet and record parameters

Install the tracelet on the vehicle roof using the supplied base plate and magnets.

• Align the tracelet centrally when possible; otherwise measure the lateral offset from the vehicle centerline.
• Keep the yaw angle at 0° (parallel to the vehicle floor). Record any deviation.
• Orient the tracelet so the SIO02 cable outlet points toward the vehicle rear.
• Measure the distances between the tracelet center and the vehicle rotation point (rear axle for buses/cars) and note them.
• Measure the installation height above ground.

Mounting parameters for buses and cars

For road vehicles the vehicle rotation point (VRP) is the rear axle. Use positive lateral values if the tracelet sits to the right of the centerline.

Mounting parameters for trams

For trams the VRP is the midpoint between bogies. Lateral offsets follow the same convention as buses.

Connect the tracelet

Place the power bank and router assembly inside the vehicle and connect the EVU04 adapter to the tracelet.

Connect the wheeltick signal

Dead-reckoning requires the vehicle wheeltick signal.

• The wheeltick signal reflects traveled distance and helps bridge GNSS/UWB outages.
• Wire the vehicle wheeltick signal to the EVU04 adapter WT pin and connect the adapter GND to vehicle ground.
• Acceptable levels: ≥ 4.8 V (high), ≤ 2.2 V (low); maximum 36 V.

The tracelet firmware must match the wheeltick rate (ticks per kilometre).

Warning

The current firmware uses a fixed wheeltick rate of 4000 ticks/km. Changing the rate requires a different firmware build—contact Ci4Rail support if you need another value.

Using an OBD adapter as a wheeltick source

If tapping the wheeltick signal is not possible (for example in a passenger car), an OBD adapter can regenerate wheelticks from vehicle speed data on CAN. One option is the Dietz OBD2 CAN-Bus interface which outputs 2500 ticks/km. This adapter does not work with electric vehicles.